Structural studies of crystalline forms of triamterene with carboxylic acid, GRAS and API molecules.

Pharmaceutical salt solvates (dimethyl sulfoxide, DMSO) of the drug triamterene with the coformers acetic, succinic, adipic, pimelic, azelaic and nicotinic acid and ibuprofen are prepared by liquid-assisted grinding and solvent-evaporative crystallization. The modified Δp rule as proposed by Cruz-Cabeza [(2012 ▸). , , 6362-6365] is in close agreement with the results of this study.

Using crystallography, topology and graph set analysis for the description of the hydrogen bond network of triamterene: a rational approach to solid form selection.

This study has demonstrated the use of crystallography, topology and graph set analysis in the description and classification of the complex hydrogen bonded network of triamterene. The aim is to give a brief overview of the methodology used to discuss the crystal structure of triamterene with a view to extending the study to include the solvates, cocrystals and salts of this compound. Graphical abstract One of the structurally significant dimers (supramolecular synthons) of triamterene identified by this study.

The ecstasy and the agony; compression studies of 3,4-methylenedioxymethamphetamine (MDMA).

MDMA (3,4-methylenedioxymethamphetamine) is a Class A substance that is usually found in a tableted form. It is only observed in one orthorhombic polymorph under ambient conditions. It shows slight positional disorder around the methlyenedioxy ring which persists during compression up to 6.

Ultrasound-assisted construction of halogen-bonded nanosized cocrystals that exhibit thermosensitive luminescence.

Multi-component organic nanocrystals that are comprised of two or more supramolecular building blocks can be used to extend the design and assembly scope of solid molecular materials. Herein, we report the use of ultrasonication to prepare halogen-bonded stilbene-based nano-cocrystals that exhibit different photoemission properties, including one- and two-phonon emission and fluorescence lifetimes, relative to those of macrodimensional crystals. The structural transformation from nano-cocrystals into nanocrystals upon heating results in a luminescence red-shift from greenish blue to yellow.

Pharmaceutical cocrystals and poorly soluble drugs.

In recent years cocrystal formation has emerged as a viable strategy towards improving the solubility and bioavailability of poorly soluble drugs. In this review the success of numerous pharmaceutical cocrystals for the improvement of the solubility and dissolution rates of poorly soluble drugs is demonstrated using various examples taken from the literature. The role of crystal engineering principles in the selection of appropriate coformers and the nature of the supramolecular synthons present within the crystals are described.

Quantifying homo- and heteromolecular hydrogen bonds as a guide for adduct formation.

An investigation into the predictability of molecular adduct formation is presented by using the approach of hydrogen bond propensity. Along with the predictions, crystallisation reactions (1a-1j) were carried out between the anti-malarial drug pyrimethamine (1) and the acids oxalic (a), malonic (b), acetylenedicarboxylic (c), adipic (d), pimelic (e), suberic (f), azelaic acids (g), as well as hexachlorobenzene (h), 1,4-diiodobenzene (i), and 1,4-diiodotetrafluorobenzene (j); seven (1a to 1g) of these successfully formed salts. Five of these seven salts were found to be either hydrated or solvated.

A cocrystal strategy to tune the luminescent properties of stilbene-type organic solid-state materials.

The one- and two-photon luminescence of stilbene-type solid-state materials can be tuned and controlled from blue to yellow color by a supramolecular cocrystal method.

pK(a)-directed host-guest assemblies: rational analysis of molecular adducts of 2,4-diamino-6-methyl-1,3,5-triazine with various aliphatic dicarboxylic acids.

Molecular adducts of 2,4-diamino-6-methyl-1,3,5-triazine (1) have been prepared with various aliphatic dicarboxylic acids. The molecular complexes (1 a-1 i) thus formed by co-crystallizing 1 with oxalic, malonic, succinic, fumaric, acetylene dicarboxylic, glutaric, thiodiglycolic, diglycolic, and adipic acids have been found to give two types of host-guest assemblies that have voids or channels in a three-dimensional arrangement. The different types of host-guest arrangement appear to result from differences in the acidity of the dicarboxylic acids, that is, acids with pK(a)<3.